[openib-general] RE: registering read-only memory

[Eli Cohen]

I'm afraid that won't solve the problem. From some reason the vma of such a
region is flagged with VM_IO and that's why get_user_pages() will fail. We
need to find another way to get the physical address of such memory. One
thing I can think of is implementing something similar to follow_page(). Or
better if the kernel will export follow_page().

-----Original Message-----
From: Roland Dreier [mailto:roland at topspin.com]
Sent: Thursday, May 26, 2005 10:09 PM
To: Eli Cohen
Cc: Michael S. Tsirkin; openib-general at openib.org
Subject: Re: registering read-only memory


OK, I think I understand the problem.  The compiler puts a string
defined with "const char *foo" on a read-only page, but in
uverbs_mem.c we always pass write=1 to get_user_pages().  I need to
fix the code so that it only asks for writeable pages if we're
registering with writable permissions.

 - R.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openfabrics.org/pipermail/general/attachments/20050526/1e8ba883/attachment.html>